Metallic dental filling composition



Patented Nov. 14, 1933 UNITED STATES METALLIC DENTAL FILLING COMPOSITIONFriedrich Hauptmeyer, Essen, Germany N Drawing.

Application December 22, 1928,

Serial No. 328,056, and in Germany March 1,

1 Claim. (Cl. 106-6) This invention relates to a plastic composition tobe used for filling carious teeth. The object of the invention is toprovide a composition of this kind which can be polished well,

5 which possesses high resistance to wear, and

which is neutral to chemical agents. This object is obtained accordingto the invention by making a mixture of a chemically neutralchromium-nickel iron or steel alloy in powdered condition and a dentalcement, the proportions being preferably determined so that there isjust sufficient of the metallic alloy to insure the desired highresistance to wear and good polishability.

Any of the known chemically neutral chromium-nickel iron alloys, orchromium-nickel steel alloys may be used, and they may contain othercomponents not jeopardizing the advantageous property of chemicalneutrality. As ex- 20 amples of the alloys which may be used, referenceis made to the patents to Benno Strauss, No. 1,339,378,

1,421,776, and Harry Etchels, No. 1,522,813.

The dental filling composition may be pro- 5 duced, for example, in thefollowing manner.

Finely powdered chemically neutral chromiumnickel steel containing aboutpercent of chromium and 7 percent of nickel is mixed with one of thecements used in dental surgery, with addition of the usual settingliquid, and a paste which is at first plastic, but which concretes lateron is made thereof. The lower limit of the percentage of chromium-nickelsteel is determined by tests showing whether the mixture FriedrichI-Iauptmeyer, No.

After the cement has set, the plug is polished and then forms a toothfilling which is both chemically neutral toward all agents that comeinto consideration, and highly resistant to wear, and is far superior toamalgam filling which under certain circumstances is not harmless.

The manner in which the alloys are brought into the powdered conditionis of no importance for the present invention. They may be pulverized bymeans. of mills such as those described in the patents to C. T. Fuller,No. 1,041,769 and E. Podszus, No. 1,573,017. A still better procedure,based upon certain particular properties of the chemically neutralchromium-nickel iron and steel alloys, is as follows: A piece ofchemically neutral chromium-nickel iron or steel alloy is heated for aconsiderable time to a temperature between 500 to 900 'C., after whichit is subjected to the attack of a suitable corrosive, such as dilutesulphuric acid containing copper sulphate. The heating causes theseparation from the austenitic matrix of the alloy of carbides, whichare. segregated in the grain boundaries,

from which they are substantially washed out by the action of thecorrosive agent. Under the influence of this inter-crystallinecorrosionthe alloy first loses its metallic ring, .then becomes like leather, sothat it can be bent and crumbled in the fingers. In this condition thealloy can I easily be reduced to, an extremely fine powder and this isadvantageous because the polishability of the composition depends uponthe fineness of the metal particles. 1 I claim:

A dental filling mass consisting of a mixture of about 50% of dentalcement and about 50% of a powdered chromium-nickel iron or steel alloyneutral to chemical agents.

FRIEDRICH HAUP'IMEYER.

